<?php
    define('DB_HOST','localhost'); 
    define('DB_USER','yss'); 
    define('DB_PASS','abc123456');
    define('DB_NAME','review_app');
    // 新建连接
    $conn = new mysqli(DB_HOST,DB_USER,DB_PASS,DB_NAME);
    //检查连接
    if ($conn->connect_error) {
        die("连接失败 ".$conn->connect_error);
    }else
        echo "链接成功"
?>